Technical memo about issues with the Phantom II braking system, pedal movement, and servo gear clearances.
| Identifier | ExFiles\Box 12\5\ 05-page136 | |
| Date | 24th October 1929 | |
| Hs. {Lord Ernest Hives - Chair} c. By. {R.W. Bailey - Chief Engineer} c. Da. {Bernard Day - Chassis Design} c. Wcr. c. Mx. {John H Maddocks - Chief Proving Officer} x7420. EP {G. Eric Platford - Chief Quality Engineer} 5/H24.10.29. X. 7360 X7370 X. 7420 X7782 Re. PHANTOM II BRAKES. We find even on a new chassis or complete car, and although the brake clearances be set normally correct, that if the brakes are used fairly excessively, the brake pedal movement is insufficient, and come on to the floorboards to the extent that a certain amount of effective braking is lost. A customer using his car in hilly districts, where the brakes are used fairly excessively, and suddenly having to apply the brakes for quick stoppage, would find that the pedal came on the floorboards and the brakes not fully effective. Again, if the brakes are adjusted by means of the adjustment provided, and as instructed in the Instruction Book, the clearance is then definitely insufficient, and the brakes will be continually dragging. With this type of brake we consider some finer range of adjustment is required. We bring this to your attention as a point which is likely to be complained of. It also appears necessary that the question of the servo brake clearance, as checked by the brake pedal, should be revised and reinstructed, as according to our models and chassis on test, this clearance is definitely more than the Phantom I and there does not seem to be any alteration in the Instruction Book to this effect. The same remarks apply to the initial clearance for the rear brakes, as we cannot on this type of axle control, work to the same minimum clearances as specified for the Phan.I without the brakes showing definite signs of insufficient clearance; this apart from the increased servo movement, also increases the free pedal movement. As regards the servo gear, a certain amount of movement of the pedal is lost in compressing the buffer spring and some definite working range of this buffer spring should be specified so as to obtain a definite servo brake clearance with a definite pedal movement. We suggest that the whole question of brake action, brake adjustment and brake clearances should be gone into, and the Instruction Book which is now in print should be revised in this respect. | ||
From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).